A 47-year-old Burbank runner with plans to tackle the Boston Marathon on Monday decided not to go for health reasons, according to her parents.

With multiple marathons under her belt, Kimberlee Morgan sat the Boston Marathon out this year per the request of her doctor, said her mother Ita Moran.

“I would’ve had a nervous breakdown if she had been running,” Moran said Monday afternoon, while watching the aftermath of the explosions unfold on TV with her husband. “It’s absolutely terrible – all those innocent people.”

About three hours into the 26.2-mile race, an explosion went off at the Boylston Street finish line, followed by a second explosion seconds later. Three people died and more than 100 were injured, some of them gravely.

[Updated April 16, 2013 : This post was updated to reflect a higher number of casualities.]

Morgan’s father, Nick Moran, said he couldn’t believe the news.

“She would’ve been in the middle or the front because she runs pretty fast,” he said.

Five other Burbank residents were registered to run in Monday’s marathon.

According to marathon data, Burbank resident Christopher Gilbertson finished the race in just under 3 1/2 hours. Two others, Chu Shin and Tim Hwang, reportedly made it halfway, records show.